Pressure-sensitive adhesive layers with surface-enriched stripes and methods of making

ABSTRACT

Herein are disclosed a pressure-sensitive adhesive layer on a substrate, the adhesive layer containing stripes of first and second pressure-sensitive adhesives. The surface of the adhesive layer that faces the substrate is surface-enriched with the first pressure-sensitive adhesive. Methods of making are disclosed.

BACKGROUND

Pressure-sensitive adhesives (PSAs) are widely used for various bondingapplications.

SUMMARY

In broad summary, herein is disclosed an article comprising apressure-sensitive adhesive layer on a substrate, the adhesive layercomprising stripes of first and second pressure-sensitive adhesives. Thesurface of the adhesive layer that faces the substrate issurface-enriched with the first pressure-sensitive adhesive. Methods ofmaking such articles are also disclosed. These and other aspects of theinvention will be apparent from the detailed description below. In noevent, however, should this broad summary be construed to limit theclaimable subject matter, whether such subject matter is presented inclaims in the application as initially filed or in claims that areamended or otherwise presented in prosecution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross sectional slice view of a portion of anexemplary article as disclosed herein.

FIG. 2 is a schematic cross sectional slice view of a portion of anotherexemplary article as disclosed herein.

FIG. 3 is a schematic cross sectional slice view of a portion of anotherexemplary article as disclosed herein.

Like reference numbers in the various figures indicate like elements.Some elements may be present in identical or equivalent multiples; insuch cases only one or more representative elements may be designated bya reference number but it will be understood that such reference numbersapply to all such identical elements. Unless otherwise indicated, allfigures and drawings in this document are not to scale and are chosenfor the purpose of illustrating different embodiments of the invention.In particular the dimensions of the various components are depicted inillustrative terms only, and no relationship between the dimensions ofthe various components should be inferred from the drawings, unless soindicated.

Although terms such as “top”, bottom”, “upper”, lower”, “under”, “over”,“front”, “back”, “up” and “down”, and “first” and “second” may be usedin this disclosure, it should be understood that those terms are used intheir relative sense only unless otherwise noted. The terms inward,outward, and lateral have particular meanings as defined later herein.The term “adhesive” as used herein means a pressure-sensitive adhesive.As used herein as a modifier to a property or attribute, the term“generally”, unless otherwise specifically defined, means that theproperty or attribute would be readily recognizable by a person ofordinary skill but without requiring absolute precision or a perfectmatch (e.g., within +/−20% for quantifiable properties). The term“substantially”, unless otherwise specifically defined, means to a highdegree of approximation (e.g., within +/−10% for quantifiableproperties) but again without requiring absolute precision or a perfectmatch. Terms such as same, equal, uniform, constant, strictly, and thelike, are understood to be within the usual tolerances or measuringerror applicable to the particular circumstance rather than requiringabsolute precision or a perfect match.

DETAILED DESCRIPTION

Shown in FIG. 1 is a schematic cross sectional slice view of a portionof an exemplary article (viewed along the long axis of stripes 20 and40) as disclosed herein. The article comprises a substrate 10 with afirst major surface 11 and a second major surface 12 that facesoppositely from first major surface 11. A primary adhesive layer 5 isdisposed on first major surface 11 of substrate 10. Adhesive layer 5comprises a plurality of stripes of a first pressure-sensitive adhesive20 and of a second pressure-sensitive adhesive 40, arranged in agenerally alternating pattern across a lateral extent “l” of substrate10, as shown in exemplary manner in FIG. 1. (By a lateral direction, andthe resulting lateral extent, is meant a direction that is substantiallyperpendicular to the long axes of the stripes). First pressure-sensitiveadhesive 20 and second pressure-sensitive adhesive 40 may be any two (ormore) pressure-sensitive adhesives that differ in properties (e.g., byvirtue of differing in composition), as discussed in detail laterherein. Substrate 10 may be any desired substrate, e.g. a release liner,as discussed in detail herein.

As stated above, stripes of pressure-sensitive adhesives 20 and 40 arearranged in a generally alternating pattern. An exemplary version ofthis is as shown e.g. in FIGS. 1-3, in which the following pattern isillustrated: [40/20/40/20 . . . ]. However, the concept of generallyalternating also includes patterns in which any selected stripe (whetherof adhesive 20 or 40) can be provided in the form of two or moresub-stripes. For example, one of e.g. stripes 20 or 40 or could beprovided as two sub-stripes e.g. with a gap in between, instead of as asingle stripe as shown in FIG. 1. Thus, for example, a generallyalternating pattern includes such patterns as [20/(40/40)/20/(40/40) . .. ]; that is, a pattern in which two 40 sub-stripes are followed by asingle 20 stripe); and, [(20/20)/(40/40/40) . . . ]; that is, a patternin which two 20 sub-stripes are followed by three 40 sub-stripes), andso on. In many embodiments, stripes of pressure-sensitive adhesives 20and 40 will be elongated so as to comprise long axes, although such longaxes do not necessarily have to be strictly linear.

Individual stripes of adhesives 20 and 40 of adhesive layer 5 may haveany desired average lateral width. In various embodiments, an individualstripe may comprise an average width that is at least about 0.1, 0.2, or0.4 mm (noting that the width of a stripe may occasionally vary somewhatalong the long axis of the stripe). In further embodiments, anindividual stripe may comprise an average lateral width that is at mostabout 2, 1, or about 0.6 mm. Stripes of a particular type (e.g., ofadhesive 20 or 40) do not all have to be of the same width; moreover,stripes 20 do not have to be the same width as stripes 40. As discussedextensively herein, the width of at least some stripes 20 (and 40) willbe different on the side of the stripe that faces substrate 10, from thewidth on the opposite side. For such stripes, the average widths referto the average of the widths on the two sides of the stripe.

Individual stripes 20 and 40 may have any suitable average thickness (inthe inward-outward direction relative to substrate 10, as designated inFIG. 1). In various embodiments, stripes 20 and/or 40 may comprise anaverage thickness of at least about 10, 20, 40, or 60 microns. Infurther embodiments, stripes 20 and/or 40 may comprise an averagethickness of at most 140, 100, 80, or 70 microns. In some embodiments,all stripes of a particular type may be similar in thickness and/orstripes 40 may have approximately the same average thickness as that ofstripes 20. However, it may not be required that all stripes haveidentical thickness or even similar thickness, as will be evident fromlater discussions herein. As discussed herein, the thickness of at leastsome stripes 20 (and 40) will vary across the lateral width of thestripe. For such stripes, the average thickness can be measured at ornear the lateral center of the stripe (e.g., thickness T_(lc) as shownin FIG. 1). In some embodiments, liner-facing major surfaces 21 ofstripes 20 may be coplanar with liner-facing major surfaces 41 ofstripes 40.

Stripes 20 and 40 may be provided at any desired pitch (i.e., thecenter-to-center distance between adjacent stripes). It may beadvantageous that the pitch be relatively small e.g. so that arelatively smooth and continuous removal process (e.g., when peeling aconventional tape, or when stretching a stretch-releasable tape) may beobtained. Thus, in various embodiments, the center-to-center pitchbetween adjacent stripes may be at most about 4, 2.5, 2, 1.5, or 1 mm.In further embodiments, such a center-to-center pitch may be at leastabout 0.5, 1, 1.5, or 2 mm. The pitch does not have to be constant, butcan be if desired. Individual stripes 20 and/or 40 may often becontinuous along their long axis, but can be discontinuous (interrupted)if desired. However, in any case, such stripes will be distinguished(i.e., by way of each stripe being comprised of segments that eachcomprise a long axis that is coincident with the long axis of thestripe) from e.g. adhesives that are deposited on a surface as an arrayof dots by way of e.g. gravure coating, screen printing, and the like.

Surface Enrichment

At least selected pairs of adjacent stripes of first adhesive 20 andsecond adhesive 40 will be configured (as shown in exemplary embodimentin FIG. 1) so that a lateral edge portion 25 of first pressure-sensitiveadhesive stripe 20 inwardly underlies a lateral edge portion 45 ofsecond pressure-sensitive adhesive stripe 40. (Many stripes of thisgeneral type will comprise two such lateral edge portions 25, as showne.g. in FIG. 1). As can be appreciated from the exemplary illustrationof FIG. 1, by inwardly underlies means that a straight line that ispassed in an outward→inward direction through portion 45 of secondadhesive stripe 40 will pass through portion 25 of first adhesive stripe20 before reaching substrate 10. Thus in such arrangements, rather thaninterface 48 between adjacent edge surfaces of stripes 20 and 40 beingsubstantially perpendicular to the major plane of substrate 80,interface 48 may run at an angle that is e.g. far removed from theperpendicular. Moreover, the angle of interface 48 does not necessarilyhave to be constant, again as illustrated in exemplary embodiment inFIG. 1. (In some such embodiments the angle of interface 48 may decreaseas it approaches surface 21 of stripe 20, so that portion 25 may e.g.comprise a laterally-elongated flange portion as shown in FIG. 1.)

In such embodiments lateral edge portion 25 of first pressure-sensitiveadhesive stripe 20 may thus comprise a first surface 27 that is incontact with surface 11 of substrate 10; and, at least some part of edgeportion 25 may further comprise a second, generally oppositely-facingsurface 28 that is in contact with (at interface 48) a surface 47 of alateral edge portion 45 of second pressure-sensitive adhesive stripe 40.It will be appreciated from inspection of FIG. 1 that the condition thatsurface 28 (which contacts second adhesive 40) is “generally oppositelyfacing” with respect to major surface 27 (which contacts substrate 10)does not require that these two surfaces (of edge portion 25) must facediametrically away from each other, nor does it require that theorientation of the two surfaces remains constant over the lateral extentof lateral edge portion 25 of stripe 20. Rather, it merely implies thatin lateral edge portion 45 of second adhesive stripe 40, surface area 47of inward major surface 41 of second adhesive stripe 40, which area 47would ordinarily be expected to contact substrate 10, is instead incontact with outward surface 28 of lateral edge portion 25 of firstadhesive stripe 20 (at interface 48).

Significant advantages can be imparted by this general type ofarrangement (which is referred to herein as surface enrichment of firstadhesive 20). For example, a first pressure-sensitive adhesive 20 mayprovide enhanced performance in a particular application, or maycomprise a property that is particularly useful in a given situation.However, such an adhesive may be e.g. more expensive than the secondadhesive 40 (or there may be some other reason why it is desired tominimize the overall amount of first adhesive 20). The arrangementsdisclosed herein allow that in lateral edge portions 25, first adhesive20 can be preferentially provided (e.g. in a relatively thin surfacelayer) against the surface of substrate 10 instead of second adhesive 40being present in such locations. That is, the area of first surface 21of first adhesive 20 that is against surface 11 of substrate 10 may begreater than that expected based on the overall amounts of the first andsecond adhesives in adhesive layer 5.

It will be appreciated that in the particular circumstance thatsubstrate 10 is a release liner, upon the separation of adhesive layer 5and release liner 10 from each other, surface 21 of first adhesive 20that is thus exposed will be in position to be adhesively bonded to asurface, e.g. to a mounting surface of a building component. Theenrichment of first adhesive 20 at this surface (compared e.g. to thefraction of first adhesive 20 at the opposite surface of adhesive layer5) can thus provide enhanced bonding to certain surfaces whileminimizing the amount of first adhesive 20 that is used in adhesivelayer 5 as a whole. Conversely, the oppositely-facing side of adhesivelayer 5 may become enriched in second adhesive 40 (although this may notalways happen, as discussed later herein). This may be of little or noconsequence since this oppositely-facing side of adhesive layer 5 may bee.g. bonded to a surface (e.g., of a tape backing) to which enhancedbonding is not required.

In embodiments of this type (e.g. as shown in FIG. 1), at least some offirst adhesive stripes 20 may each comprise a laterally-central portion26 with a second major surface 22 that faces generally opposite firstmajor surface 21 of first adhesive stripe 20, which second major surface22 of laterally-central portion 26 of first adhesive stripe 20 is not incontact with (e.g., is not covered by), second adhesive stripe 40. Inother words, major surface 22 of laterally-central portion 26 may be anexposed surface after the formation of adhesive layer 5, so that exposedsurface 22 can be e.g. bonded to e.g. a backing. Thus, at least portionsof such an adhesive layer 5 may avoid the potential disadvantages ofhaving an internal interfacial boundary that is present between firstand second adhesives 20 and 40 and that extends over most or all of thearea of adhesive layer 5. Such an arrangement can be differentiated frome.g. conventional multilayer coating of layers of different adhesives.

In further detail, a laterally-central portion 26 of a selected firststripe 20 may comprise first and second lateral edge portions 25laterally extending therefrom on the side of stripe 20 that facessubstrate 10, as shown in FIG. 1. For a first stripe 20 of this generaltype, the lateral width w_(le) of each lateral edge portion 25 can becompared to the width W_(lc) of laterally central portion 26, as shownin FIG. 1. In various embodiments, such a lateral width w_(le) of alateral edge portion 25 may be at least 10, 20, 40, or even 60% or more,of the lateral width W_(lc) of laterally central portion 26. In furtherembodiments, such a lateral width of lateral edge portion 25 may be lessthan about 70, 50, 30, 20, or 10% of the lateral width of laterallycentral portion 26. The (total) substrate-side lateral width of eachstripe 20 in which surface-enrichment is present, will be given by thesum W_(lc)+w_(le)+w_(le). (It is noted however that in some embodimentsa stripe of a first adhesive 20 might be surface-enriched only along onelateral edge, and might comprise an adhesive-free gap along its otherlateral edge, in which case the substrate-side width of such a stripewould be W_(lc)+w_(le)). The opposite-side lateral width will be givenby W_(lc). In various embodiments, the substrate-side lateral width of astripe 20, may be greater than the opposite-side lateral width of thatstripe 20, by a factor of at least about 1.2, 1.6, 2.0, or 2.5.

The thickness t_(le) of a lateral edge portion 25 may be compared to theaverage thickness T_(lc) of laterally-central portion 26 of firstadhesive stripe 20. Although the thickness t_(le) may vary over thelateral extent of edge portion 25 (as shown in FIG. 1), a localthickness can be measured in any particular part of edge portion 25.Thus, in various embodiments, at least a part of lateral edge portion 25of adhesive stripe 20 (e.g., toward the laterally-outermost edge ofportion 25) may comprise a thickness t_(le) that is less than about 60,40, 20, or 10% of the average thickness T_(lc) of the laterally-centralportion 26 of first adhesive stripe 20.

Liner-Side & Opposite-Side Area Fractions

For each of first and second adhesives 20 and 40 on each major surfaceof adhesive layer 5, an area fraction can be defined that is thefraction (percentage) of the total area of that surface of adhesivelayer 5 that is collectively provided by the stripes of that adhesive.The surface-enrichment of first adhesive 20 may be characterized interms of the area fractions that are provided by each adhesive at eachsurface of adhesive layer 5. Specifically, for first adhesive 20 asubstrate-side area fraction can be obtained, and an opposite-side areafraction can be obtained. If little or no surface-enrichment is present,the substrate-side and opposite-side area fractions for first adhesive20 will typically be very similar to each other. However, ifsurface-enrichment is present the substrate-side area fraction and theopposite-side area fraction provided by first adhesive 20 may differsignificantly from each other. (The same holds true for second adhesive40).

In other words, the fraction that first adhesive 20 provides of theadhesive materials present at the surface of adhesive layer 5 that is incontact with substrate 10 can be determined. This can be compared to thefraction that first adhesive 20 provides of the adhesive materialspresent at the opposite surface of adhesive layer 5. Whensurface-enrichment is present at the substrate-side surface of adhesivelayer 5, the difference between the substrate-side and opposite-sidearea fractions of first adhesive 20 (and corresponding parameters forsecond adhesive 40) can characterize the extent of suchsurface-enrichment. Specifically, the ratio of these two area fractionscan be obtained. Thus to summarize with reference to FIG. 1, a measureof surface-enrichment at the surface 21 of adhesive layer 5 that is incontact with substrate 10, can be obtained by ratioing the area fractionthat surface 21 occupies (of surfaces 21 and 41 of the first and secondadhesives respectively) on the substrate side, to the area fraction thatsurface 22 occupies (of surfaces 22 and 42 of the first and secondadhesives respectively) on the opposite side. Such a ratio can provide aquantitative measure of the surface enrichment of first adhesive 20 onthe substrate-facing major surface of adhesive layer 5.

In embodiments in which little or no surface enrichment is present, sucha surface-enrichment ratio may be about 1 (i.e., a baseline value).However, in embodiments in which surface enrichment occurs, such a ratiomay be e.g. about 1.2, 1.4, 1.6, 1.0, 2.0, or 2.4. By way ofillustration, in the exemplary representation of FIG. 1, thesubstrate-side area fraction provided by first surface 21 of firstadhesive 20 appears to be in the range of 70% (assuming that the stripesare present at roughly equal nominal widths). The opposite-side areafraction provided by second surface 22 of first adhesive 20 appears tobe in the range of 50%. Thus, the surface enrichment ratio would beabout 70/50, or about 1.4.

In some embodiments, the general arrangement presented in FIG. 1 may beexploited to an extreme. That is, as shown in exemplary manner in FIG.2, the lateral edge portions 25 and 25′ of two first stripes 20 and 20′that laterally flank a second adhesive stripe 40, may extend so farlaterally toward each other that they meet and thus completely underliethe second stripe 40. That is, in such cases essentially 100% of theadhesive surface area of adhesive layer 5 that contacts surface 11 ofsubstrate 10, may be supplied by first adhesive 20. With arrangementssuch as this, the potential problem of failure at the interface betweensurface 28 of first adhesive 20, and surface 47 of second adhesive 40,does not seem to have been encountered (that is, constructions of thistype still exhibit acceptable peel and shear strength). While notwishing to be limited by theory or mechanism, it may be that theparticular manner in which such arrangements are achieved may result instronger and/or longer-lasting interfacial bonding between the surfacesof the two adhesives. And, of course, the presence of laterally-centralportions 26 of first adhesive 20, in which first adhesive 20 providesboth of the bonding surfaces of adhesive layer 5, and extendscontinuously therebetween (with no interface between first adhesive 20and second adhesive 40 being present in this area of adhesive layer 5),may also be beneficial.

It is noted that in embodiments in which surface enrichment occurs tothe extent that two lateral edge portions 25 and 25′ extend so farlaterally toward each other that they meet, there may be no visiblyobvious dividing line between the two stripes 20 and 20′ from which eachedge portion extended. In this special case, items 20 and 20′ can stillbe considered to be individual stripes that are distinguishable fromeach other, and each can be considered to comprise an elongate length(i.e. in the direction in which each stripe was deposited onto themoving substrate 10) and a width. However, it is further noted that inthe case of a conventional, laterally continuous adhesive layer thatmight be arbitrarily divided into lateral sections each with a width,such arbitrarily selectable sections or widths, that are notdistinguishable from each other, cannot be equated with the term“stripes” as used herein. It is thus emphasized that (even in the caseof essentially complete surface enrichment of first adhesive 20 at thesurface of substrate 10), the stripe-coating arrangements presentedherein are distinguished from those achieved by conventional multilayercoating, e.g. by coating a layer of a first adhesive onto a substrateand coating a layer of a second adhesive atop the first adhesive toachieve a multilayer stack. For example, at the very least suchconventional multilayer approaches would not be expected to give rise tolateral edge portions 25 and 45 of stripes 20 and 40 with angledinterfaces 48 therebetween, and which lateral edge portions 25 of astripe 20 are readily distinguishable from a laterally-central portion26 of the stripe, as discussed above.

Although the above-discussed surface enrichment typically occursprimarily at the major surface of adhesive layer 5 that faces substrate10, some surface enrichment has occasionally been observed at theoppositely-facing surface of adhesive layer 5, as shown in exemplarymanner in FIG. 3. That is, a stripe of first adhesive 20 may exhibit oneor more secondary lateral edge portions 29 on the opposite surface fromthe above-described lateral edge portions 25. Such arrangements mayprovide further advantages in allowing the surface area of exposed firstadhesive 20 to be maximized on both bonding surfaces of adhesive layer5, while using a minimal amount of first adhesive 20. In the specialcase in which some surface enrichment occurs at the opposite surface,the minimum lateral width of stripe 20 (e.g. as designated by thedouble-headed arrow of FIG. 3) is used as the opposite-side lateralwidth (Wig) for purposes of comparison with the substrate-side lateralwidth, for calculation of area ratios, etc.)

The surface-enrichment of a first adhesive 20 at the substrate-facingsurface of an adhesive layer 5 may provide advantages in any of a numberof situations and applications. By way of illustration, Working Examplesare presented herein in which first adhesive 20 is a silicone-basedadhesive that is shown to impart enhanced ability to preserve anadhesive bond to a so-called architectural paint, even in the presenceof e.g. high humidity. These results are demonstrated by way of anElevated Humidity/Static Shear Test. It is emphasized however that theparticular adhesives that were chosen, and the particular testing thatwas done, are illustrative in nature. Any first and second adhesives ofdiffering properties may be used, for any suitable purpose, with thefirst adhesive being surface-enriched to achieve any desired end.

Volume Fractions

The above-presented arrangements can provide benefits by allowing theactual bonding surface area provided by a first adhesive to be greaterthan that which would be expected based on the volume fraction at whichthe first adhesive is present in adhesive layer 5. By the volumefraction provided by an adhesive (e.g., a first adhesive) is meant thefraction (percentage) of the total volume of adhesive layer 5 that iscollectively occupied by the stripes of that adhesive.

In addition to the already-discussed surface-enrichment effects, thevolume fraction at which first and second adhesives 20 and 40 arepresent in adhesive layer 5 may be manipulated by arranging for thethickness of the stripes of first adhesive 20 to be different from thethickness of stripes of second adhesive 40. In some embodiments, thethickness of the stripes of first adhesive 20 relative to that of thestripes of second adhesive 40, may be advantageously minimized so as touse a lower volume fraction of first adhesive 20. In such embodiments,the thickness of stripes of second adhesive 40 may be greater than thatof first adhesive 20, by a factor of at least about 1.2, 1.6, 2.0, 2.5,or 3.0. In other embodiments, the thickness of the stripes of firstadhesive 20 (more specifically, the thickness of the as-depositedflowable liquid precursor to first adhesive 20) may be advantageouslyincreased relative to that of the stripes of second adhesive 40, e.g. soas to promote the surface-enrichment effect, as discussed later herein.In such embodiments, the thickness of stripes of first adhesive 20 maybe greater than that of second adhesive 40, by a factor of at leastabout 1.2, 1.6, 2.0, 2.5, or 3.0. In some circumstances it may bedesired that the average thickness of first adhesive stripes 20 besimilar to the average thickness of second adhesive stripes 40. Thus insome embodiments, the average thickness of first adhesive stripes 20 iswithin plus or minus 40, 20, 10, or 5% of the average thickness ofsecond adhesive stripes 40.

In various embodiments, first adhesive 20 may be provided at a volumefraction of at least about 30, 35, 40, 50, or 60%. (The balance ofadhesive layer may be provided by second adhesive 40, alone or incombination with third or even fourth adhesives). In furtherembodiments, first adhesive 20 may be provided at a volume fraction ofat most about 90, 85, 80, 70, 60, 50, or 40% (noting that Tables 1 and 2denote arrangements in which the volume fraction of first adhesive 20 isestimated to be as high as about 82%).

Pressure-Sensitive Adhesives

First adhesive 20 and second adhesive 40 are both pressure-sensitiveadhesives. (While the simplest example of a two-adhesive system isdiscussed herein, it will be appreciated that third, fourth, or evenmore adhesives can be present, if desired.) The only requirement is thatfirst and second adhesives possess one property in which they differfrom each other (specifically, some e.g. intensive property other thanextensive (e.g., geometric) properties such as width and thickness). Aproperty in which the first and second adhesives might differ might be(but is not limited to) one or more of melting point, glass transitiontemperature, elastic modulus, peel strength, shear strength, hardness,moisture-vapor transmission, water-repellency, oil absorption,solubility in water and/or in organic solvents, temperature resistance,UV-resistance, and so on. It will be appreciated such a difference inproperties might be achieved e.g. by a difference in composition;however, even adhesives of very similar composition might exhibitdifferent properties e.g. by way of having been exposed to a differentprocessing history. That is, the first and second adhesive (whethersimilar in composition or not) might differ in e.g. percentcrystallinity, free volume, crosslink density, and so on. In someembodiments, one or both of first and second adhesives 20 and 40 may bea repositionable adhesive. In alternative embodiments, neither of firstand second adhesives 20 and 40 are repositionable.

Pressure-sensitive adhesives are normally tacky at room temperature andcan be adhered to a surface by application of, at most, light fingerpressure and thus may be distinguished from other types of adhesivesthat are not pressure-sensitive. A general description ofpressure-sensitive adhesives may be found in the Encyclopedia of PolymerScience and Engineering, Vol. 13, Wiley-Interscience Publishers (NewYork, 1988). Additional description of pressure-sensitive adhesives maybe found in the Encyclopedia of Polymer Science and Technology, Vol. 1,Interscience Publishers (New York, 1964). In at least some embodiments,a pressure-sensitive adhesive may meet the Dahlquist criterion describedin Handbook of Pressure-Sensitive Adhesive Technology, D. Satas, 2^(nd)ed., page 172 (1989). This criterion defines a pressure-sensitiveadhesive as one having a one-second creep compliance of greater than1×10⁻⁶ cm²/dyne at its use temperature (for example, at temperatures ina range of from 15° C. to 35° C.).

Any suitable pressure-sensitive adhesive of any suitable composition andwith any suitable properties may be used for either or both of first andsecond pressure-sensitive adhesives 20 and 40. In some embodiments, atleast one of first and second adhesives 20 or 40 is a silicone-basedpressure-sensitive adhesive. In some embodiments, first adhesive 20 is afirst silicone-based adhesive with a first set of properties, and secondadhesive 40 is a second silicone-based adhesive with a second set ofproperties (and that may differ in composition from the first adhesive).Such adhesives typically include at least one silicone elastomericpolymer, and that may contain other optional components such astackifying resins. The silicone elastomeric polymer may be a siliconeblock copolymer elastomer comprising hard segments that each comprise atleast one polar moiety. By a polar moiety is meant a urea linkage, anoxamide linkage, an amide linkage, a urethane linkage, or aurethane-urea linkage. Thus, suitable silicone block copolymerelastomers include for example, urea-based silicone copolymers,oxamide-based silicone copolymers, amide-based silicone copolymers,urethane-based silicone copolymers, and mixtures thereof. Suchsilicone-based pressure sensitive adhesives are described in detail inpending U.S. patent application Ser. No. 61/838,504, Entitled “ArticleComprising Pressure-Sensitive Adhesive Stripes”, filed evendateherewith, which is incorporated herein by reference in its entirety.Other silicone-based adhesives may be those based e.g. on thermallycurable (e.g., platinum-cured, peroxide-cured, moisture-cured siliconepolymers, etc.), as are well-known to the skilled artisan. Suchsilicones may not necessarily comprise any of the above-listed hardsegments.

Silicone-based pressure-sensitive adhesive compositions (whether relyinge.g. on a block copolymer with hard segments, or any other type ofsilicone elastomer) may often include an MQ tackifying resin.Silicone-based adhesives, of any of the above-discussed types andvariations, may be provided in any suitable form to be formed intostripes 20 and/or 40. For example, such an adhesive may be provided inthe form of a precursor liquid that is a flowable liquid that can bedeposited onto substrate 10 to form stripes of the precursor liquid,which precursor can then be transformed into the silicone-based adhesivein its final form. Thus, a precursor flowable liquid might be e.g. a100% solids mixture suitable for e.g. hot melt coating, or a water-borneemulsion (e.g. latex), or a solution in one or more suitable solvents,as discussed later herein.

In some embodiments, at least one of first and second adhesives 20 or 40is an organic polymeric pressure-sensitive adhesive. In someembodiments, first adhesive 20 is a first organic polymeric adhesivewith a first set of properties, and second adhesive 40 is a secondorganic polymeric adhesive with a second set of properties (and that maydiffer in composition from the first adhesive). An organic polymericpressure-sensitive adhesive by definition includes less than 10 weightpercent of a silicone-based pressure-sensitive adhesive (dry weightbasis). In various embodiments, such an adhesive may comprise less than4, 2 or 1% of a silicone-based adhesive. In many embodiments, such anadhesive will contain substantially no (i.e., less than 0.2 weightpercent) of a silicone-based pressure-sensitive adhesive. It willhowever be appreciated that in some circumstances such an adhesive maycomprise some small amount (e.g., less than 2.0, 1.0, 0.4, 0.2, 0.1, or0.05 weight percent) of silicone-containing additive (e.g., emulsifier,plasticizer, stabilizer, wetting agent, etc.). Such circumstances, inwhich one or more silicone-containing additive(s) is/are present forsome purpose other than imparting pressure-sensitive properties to theadhesive, cannot cause such an adhesive to be considered to be asilicone-based adhesive.

By organic polymeric pressure-sensitive adhesive is meant that theadhesive is based on at least one organic polymeric elastomer(optionally in combination with other components such as one or moretackifying resins). It will be appreciated that an organic polymericadhesive does not have to be based on an organic polymeric elastomerthat is purely hydrocarbon (although this may be done if desired).Rather, the presence of heteroatoms (such as O, N, Cl, and so on) ispermitted (whether in the backbone of the elastomer chain and/or in asidechain thereof), as long as the presence of the specific heteroatomSi is minimized according to the criteria outlined above.

General categories of exemplary materials which may be suitable for usein an organic polymeric pressure-sensitive adhesive include e.g.elastomeric polymers based on natural rubber; synthetic rubber (e.g.,butyl rubber, nitrile rubber, polysulfide rubber); block copolymers; thereaction product of acrylate and/or methacrylate materials; and so on.(As used herein, terms such as (meth)acrylate, (meth(acrylic), and thelike, refer to both acrylic/acrylate, and methacrylic/methacrylate,monomer, oligomers, and polymers derived therefrom). Specific polymersand/or copolymers and/or monomer units suitable for inclusion in such anelastomeric polymer of such an adhesive may include, but are not limitedto: polyvinyl ethers, polyisoprenes, butyl rubbers, polyisobutylenes,polychloroprenes, butadiene-acrylonitrile polymers, styrene-isoprene,styrene-butylene, and styrene-isoprene-styrene block copolymers,ethylene-propylene-diene polymers, styrene-butadiene polymers, styrenepolymers, poly-alpha-olefins, amorphous polyolefins, ethylene vinylacetates, polyurethanes, silicone-urea polymers, polyvinylpyrrolidones,and any combinations (blends, copolymers, etc.) thereof. Examples ofsuitable (meth)acrylic materials include polymers of alkyl acrylate ormethacrylate monomers such as e.g. methyl methacrylate, ethylmethacrylate, n-butyl methacrylate, methyl acrylate, ethyl acrylate,n-butyl acrylate, iso-octyl acrylate, iso-nonyl acrylate, 2-ethyl-hexylacrylate, decyl acrylate, dodecyl acrylate, n-butyl acrylate, hexylacrylate, octadecyl acrylate, octadecyl methacrylate, acrylic acid,methacrylic acid, acrylonitrile, and combinations thereof. Examples ofsuitable commercially available block copolymers include those availableunder the trade designation KRATON from Kraton Polymers, Houston, Tex.Any of these or other suitable materials may be used in any desiredcombination. A general description of some useful organic polymericpressure-sensitive adhesives may be found in the Encyclopedia of PolymerScience and Engineering, Vol. 13, Wiley-Interscience Publishers (NewYork, 1988). Additional descriptions of some useful organic polymericpressure-sensitive adhesives may be found in the Encyclopedia of PolymerScience and Technology, Vol. 1, Interscience Publishers (New York,1964).

If desired, a tackifying resin may be included in an organic polymericadhesive. (Those of ordinary skill will appreciate that some elastomersmay be self-tacky and thus may require little or no added tackifyingresin.) Any suitable tackifying resin or combination thereof may beused. Suitable tackifying resins may include e.g. wood rosins andhydrogenated derivatives thereof, tall oil rosins, terpene resins,phenolic resins, polyaromatics, petroleum-based resins, (e.g. aliphaticC5 olefin-derived resins) and so on. Additionally, pressure-sensitiveadhesive 40 can contain additives such as plasticizers, fillers,antioxidants, stabilizers, pigments, and the like.

It may be convenient (e.g., for masking and/or stretch-release uses),that the components of an organic pressure-sensitive adhesive be chosenso as to provide good adhesion to a surface, while also being removableunder moderate force without leaving a residue, e.g. a visible residue.In certain embodiments, a pressure-sensitive adhesive may benatural-rubber-based, meaning that a natural rubber elastomer orelastomers make up at least about 70 wt. % of the elastomeric componentsof the adhesive (not including any filler, tackifying resin, etc.). Insome embodiments, the organic polymeric elastomer may be a hydrocarbonblock copolymer elastomer (e.g., of the general type available under thetrade designation KRATON from Kraton Polymers, Houston, Tex.). Inspecific embodiments, the block copolymer elastomer may be e.g. astyrene-butadiene-styrene (SBS) or a styrene-isoprene-styrene (SIS)block copolymer, a blend of the two, blend of either of both of thesewith a natural rubber elastomer, and so on (along with e.g. at least onetackifying resin).

Organic polymeric adhesives, of any of the above-discussed types andvariations, may be provided in any suitable form to be formed intostripes 20 and/or 40. For example, such an adhesive may be provided inthe form of a precursor liquid that is a flowable liquid that can bedeposited onto a substrate 10 to form stripes of the precursor liquid,which precursor can then be transformed into the organic polymericadhesive in its final form. Thus, a precursor flowable liquid might bee.g. a 100% solids mixture suitable for e.g. hot melt coating, or awater-borne emulsion (e.g. latex), or a solution in one or more suitablesolvents, as discussed later herein.

Substrate

Substrate 10 can be any suitable substrate upon which is it desired todispose (e.g., by coating) adhesive layer 5, whether temporarily orpermanently. In many embodiments, substrate 10 may be a release liner.Such a release liner 10 may comprise a release surface on first majorsurface 11, which release surface is suitable for releasing of apressure-sensitive adhesive therefrom. Release liner 10 may optionallycomprise a release surface, on second major surface 12. In particularembodiments, the release surface on second major surface 12 may comprisethe same, or different, release properties from those of first majorsurface 11 (in the latter case, liner 10 will thus be a so-calleddifferential-release liner, as will be well understood by the ordinaryartisan).

Release surface 11 (and release surface 12, if present) can be providedby any suitable material (or, by any suitable treatment of the surfaceof the material of which release liner 10 is made). In cases in whichadhesive layer 5 comprises e.g. organic polymeric adhesives with littleor no silicone-based adhesives, such a release surface might be e.g. anysuitable coating, for example wax or the like. Or, any suitable highmolecular weight polymeric layer (e.g., coating) might be used, e.g. apolyolefin layer such as polyethylene and so on. It will be appreciatedthat numerous layers and treatments will be suitable for such use.

If adhesive layer 5 comprises a significant amount of silicone-basedadhesive, it may be advantageous to provide release surface 11 with acomposition that enhances the ability of a silicone-based adhesive to bereleased therefrom. Fluorinated materials are often used for suchpurposes. Examples of potentially suitable materials include, but arenot limited to, fluorinated materials such as e.g. fluorochemicals,fluorocarbons, fluorosilicones, perfluoropolyethers, perfluorinatedpolyurethanes, and combinations thereof. In particular embodiments, thefluorinated release surface is provided by a fluorosilicone polymer.Particularly useful fluorosilicone release coatings may include thereaction product of a fluorosilicone polymer, anorganohydrogenpolysiloxane crosslinking agent and a platinum-containingcatalyst. A number of useful commercially available fluorosiliconepolymers are available from Dow Corning Corp. (Midland, Mich.) under theSYL-OFF and the SYL-OFF ADVANTAGE series of trade designationsincluding, e.g., SYL-OFF Q2-7786 and SYL-OFF Q2-7785. One example of auseful release liner is a fluoroalkyl silicone polycoated paper.

Substrate (e.g., release liner) 10 can be of a variety of formsincluding, e.g., sheet, web, tape, and film. Examples of suitablematerials include, e.g., paper (e.g., kraft paper, poly-coated paper andthe like), polymer films (e.g., polyethylene, polypropylene andpolyester), composite liners, and combinations thereof. Release linerscan optionally include a variety of markings and indicia including,e.g., lines, art work, brand indicia, and other information.

In some embodiments, substrate 10 may not be a release liner. In suchembodiments, adhesive layer 5 may be bonded permanently to substrate 10(meaning that the adhesive layer and the substrate cannot be removedfrom each other without unacceptably damaging or destroying one of bothof them). In such embodiments, substrate 10 can be any backing (i.e., atape backing) suitable for making any suitable kind of tape (maskingtape, sealing tape, strapping tape, filament tape, packaging tape, ducttape, electrical tape, medical/surgical tape, and so on). Backing 10 cantake any suitable form including, e.g. polymer films, paper, cardboard,stock card, woven and nonwoven webs, fiber reinforced films, foams,composite film-foams, and combinations thereof. Backing 10 may becomprised of any suitable material including e.g. fibers, cellulose,cellophane, wood, foam, and synthetic polymeric materials including,e.g., polyolefins (e.g., polyethylene, polypropylene, and copolymers andblends thereof); vinyl copolymers (e.g., polyvinyl chlorides, polyvinylacetates); olefinic copolymers (e.g., ethylene/methacrylate copolymers,ethylene/vinyl acetate copolymers, acrylonitrile-butadiene-styrenecopolymers, and so on); acrylic polymers and copolymers; andpolyurethanes. Blends of any of these may be used. In particularembodiments, oriented (e.g., uniaxially or biaxially oriented) materialssuch as e.g. biaxially-oriented polypropylene may be used. Regardless ofthe specific nature and purpose of substrate 10, adhesive layer 5 can beprovided across substantially the entirety of the width of substrate 10;or, a border may be provided along one or both edges of substrate 10 inwhich adhesive layer 5 is not present, if desired.

Secondary Substrate

In some embodiments, the side of primary adhesive layer 5 that isopposite substrate 10 can be bonded to a secondary substrate, whichbonding may be temporary or permanent as desired. As such, a secondarysubstrate might be any of the release liners described above. In otherembodiments, such a substrate can be any backing such as any of theabove-described tape backings.

In some embodiments, a substrate (whether substrate 10, or a secondarysubstrate) may be highly extensible so that in combination with adhesivelayer 5 it forms a stretch-releasable article. The term “highlyextensible” as used herein means that when the backing is stretchedalong its long axis, an elongation of at least about 150% is achievedwithout rupture or breakage of the backing. In such embodiments, such abacking may be capable of achieving an elongation of e.g. about 350,550, or 750%. Suitable highly extensible backings may include e.g. asingle layer of foam, multiple layers of foam, a single layer of film,multiple layers of film and combinations thereof. Such materials may beselected to optimize properties such as conformability and resiliency,which are useful when the article is to be adhered to surfaces havingsurface irregularities, e.g., painted drywall. Such a foam or film layermay be prepared from a variety of thermoplastic polymers including,e.g., polyolefins, vinyl polymers and/or copolymers olefinic copolymers,acrylic polymers and copolymers; polyurethanes; and so on. In someembodiments it may be particularly advantageous that a backing comprisea relatively thick and conformable polymeric foam. In variousembodiments, a backing may comprise a polymeric foam with a thickness ofat least about 0.2, 0.4, 0.8, or 1.2 mm. In further embodiments, such apolymeric foam may comprise a thickness of at most about 8, 4, or 2 mm.In various embodiments, such a polymeric foam may comprise a density ofat least about 1, 2, 4 or 6 pounds per cubic foot. In furtherembodiments, such a polymeric foam may comprise a density of at mostabout 30, 20 or 10 pounds per cubic foot.

In some embodiments adhesive layer 5 may be used in a stand-alonemanner, e.g. as a stretch-release article that is not being laminated toe.g. a highly extensible backing. In such cases, first substrate 10, andthe second substrate, may both be release liners, and adhesive layer 5may be e.g. thick enough to handle and to provide other usefulproperties when separated from one or both release liners. Thus, in suchembodiments adhesive layer 5 may comprise an average thickness of fromat least about 5, 10, 15 or 20 mils, to about 100, 80, 60, or 40 mils.In such embodiments, adhesive layer 5 should of course comprisesufficient mechanical integrity to be handleable (in the absence ofeither release liner, if necessary). Thus, in at least some suchembodiments stripes 20 and 40 should comprise sufficient bonding ofadjacent stripes to each other to provide adhesive layer 5 as a wholewith sufficient mechanical integrity.

Methods of Making

Stripes of first adhesive 20 and second adhesive 40 may be deposited onmajor surface 11 of substrate 10 e.g. by any method that allows theacceptable formation of stripes with surface-enrichment of firstadhesive 20. In general, a precursor to first adhesive 20, and aprecursor to second adhesive 40, may each be deposited onto substrate 10as a flowable liquid in any suitable form. For example, such a flowableliquid might be a 100% solids composition (e.g. a hot-melt coatingcomposition) that is deposited followed by the reaction of functionalgroups (e.g., crosslinking, polymerization, oligomerization, etc.) toimpart the desired adhesive properties to the final product. Or, such aflowable liquid might be a water-borne coating (e.g., a latex oremulsion), that is deposited followed e.g. by drying to remove thewater, and by any reaction/crosslinking if needed. In particularembodiments, first adhesive 20 and second adhesive 40 may be solventcoated—that is, each adhesive may be solubilized in an appropriatesolvent (or solvent mixture) to form a coating solution that may becoated onto substrate 10 followed by removal of the solvent(s), and byany reaction/crosslinking etc. if needed. In other words, a coatingsolution of each adhesive may be formed by dissolving the elastomer(s)(and tackifier(s) if present) in a solution, along with any otherdesired additives or ingredients, with one or more solvents that canadequately solubilize the ingredients. In such embodiments, theprecursor flowable liquids for the first and second adhesives bydefinition are not 100% solids compositions (e.g., hot melt coatableand/or extrudable compositions) and the resulting article comprises asolvent-coated adhesive layer rather than e.g. a hot-melt-coated layeror extruded layer.

Each stripe of an adhesive can be formed by expelling the precursorflowable liquid (e.g., coating solution) through an opening in a coatingdie, onto a moving surface 11 of substrate 10. Multiple stripes of e.g.first adhesive 20 can be obtained by simultaneously expelling the firstprecursor flowable liquid through multiple, laterally-spaced openings ofthe die, which may be achieved e.g. by the use of a slot die with one ormore shims provided therein to block off portions of the slot and toleave other portions of the slot open for the coating solution to passtherethrough. The same can be done for second adhesive 40 (so that thestreams of the first liquid, and the streams of the second liquid, areexpelled simultaneously from the various openings, and so that thestreams of both liquids land essentially simultaneously on the surfaceof the substrate). Generally alternating stripes of first adhesive 20and second adhesive 40 may be achieved by variations on the abovegeneral approaches. For example, an approach may be used in which thefirst and second coating solutions are fed (e.g. from first and secondseparate manifolds) to a dual layer slot die, in an arrangement in whicheach solution passes through a shim with laterally spaced-apart openingsthat dictate the nominal thickness, lateral width, and lateral pitch(center-to-center distance) of the stripes of that adhesive. The twoshims can be registered relative to each other so that so that thestripes of the two adhesives are generally alternating as desired. Sucharrangements are described in e.g. U. S. Patent Application Publication2009/0162595 to Ko.

It will be appreciated that this is merely one example and that manypossible variations exist of this general approach of deliveringprecursor flowable liquids (e.g., coating solutions) through a die ontosurface 11 of moving substrate 10 to form generally alternating stripesof first and second adhesives. In general, some such processes mayinvolve configurations in which a coating die is positioned relativelyfar from substrate 10 (e.g., in so-called extrusion coating or curtaincoating). Some such processes may use e.g. a drop die, for example amultiple-orifice drop die as disclosed in U.S. Patent ApplicationPublication 2002/0108564 to Gruenewald. Or, some such processes mayinvolve situations in which the coating die is positioned in closeproximity to substrate 10 (e.g., so-called contact coating). Asmentioned, a dual-layer slot die may be used in which two shims (thatare registered with each other) are used to respectively control theflow of the two liquids to be coated. Or, the set of shims might beintegrated together into a single uniform piece (e.g., in the mannermentioned in U.S. Patent Application Publication 2009/0162595 to Ko).Still further, the shims and/or flow passages might be e.g. machinedinto the die so as to be integrated as part of the die itself, again asmentioned by Ko. The dimensions of the openings, the flowrates of thevarious streams, and so on, can be manipulated so as to deposit thevarious streams at desired thicknesses so as to achieve any desiredthickness of the resulting adhesive stripes. Likewise, the placement anddimensions of the openings can be manipulated so as to provideadhesive-free gaps between at least some of the resulting adhesivestripes, as desired.

In some embodiments, the deposited stripes of precursor flowable liquid(e.g. coating solution) may, before any significant evaporation ofsolvent and/or solidification of the coated material has occurred, passthrough a thickness-control gap between substrate 10 and athickness-control member, e.g. in similar manner as described in U.S.Pat. No. 6,803,076 to Loukusa. Such an arrangement might be used e.g. toreduce the thickness of at least some of the stripes, to minimizevariations in the thickness of individual stripes and/or to reducevariation between the thickness of different stripes, or in general tocontrol or modify the thickness of any of the stripes in any usefulmanner. In particular, such a process may be used to promote or enhancethe herein-described lateral spreading of one or more of stripes 20 sothat at least one edge of such stripes 20 laterally displaces anadjacent edge of stripe 40. Such a thickness-control member might bee.g. a rod, a knife, a roller, a blade, or a die lip (e.g. positioneddownweb along the path of substrate 10 from the die openings). In someembodiments, a moving fluid may be impinged onto the deposited stripesto similar effect, e.g. by use of an air-knife positioned downweb of thecoating die. In other embodiments, no such passing of the depositedstripe through such a thickness-control gap, and/or use of an air-knife,may occur.

The above operations may be conveniently done by simultaneouslydepositing all of the stripes of first and second adhesives 20 and 40onto substrate 10, in a single pass of substrate 10 past a coating die.Such simultaneous coating operations may be distinguished from e.g.coating operations in which one or more stripes or layers of oneadhesive are deposited in a first pass, and one or more stripes orlayers of a second adhesive are deposited in a second pass. They mayalso be distinguished from e.g. non-simultaneous (sequential) coating oftwo different adhesives (in e.g. stripes or layers), even if suchsequential coatings are performed in-line in the same coating line.

Regardless of the particular manner in which precursor flowable liquids(e.g. coating solutions) are delivered to surface 11 of moving substrate10, in any such approach each precursor liquid is deposited (coated)onto surface 11 of substrate 10 as a stripe that is elongated in thedirection of motion of substrate 10. The solvent(s) can then be removed(e.g., by passing liner 10 through an oven) to leave behind each driedadhesive composition as an elongated stripe of the final desiredthickness, width, pitch, and so on. Of course, if anyreactive/functional components are present in the precursor liquid, theymay react, polymerize, etc., to provide the final desired product,either instead of, or in addition to, any solidification that occurs byway of removal of a coating solvent or of water. Such reaction may bepromoted by e.g. temperature, radiation, or any commonly used method.

It will be appreciated that various parameters in the solidification(e.g., drying and/or curing) process may be usefully controlled asdesired. In particular, the dwell time of the precursor flowable liquidin a relatively low-viscosity condition may be controlled so as topromote (and/or to limit) the presence and/or amount of any lateraldisplacement of a precursor stripe by the lateral edges of alaterally-adjacent precursor stripe. (Based on the discussions above, itwill be appreciated that this may allow the degree of surface enrichmentin the resulting adhesive layer to be advantageously manipulated.) Thusfor example, the distance from the coating die to any drying oven, thespeed at which the substrate is moving, the temperature of the oven, andso on, can all be controlled as desired.

In at least some embodiments, liquid-coating has been found to play auseful role in the herein-described surface-enrichment (i.e., theability to provide a higher fraction of first adhesive 20 in thesubstrate 10-facing surface of adhesive layer 5 than is present in anoverall manner in adhesive layer 5). Such coating processes have beenfound to be effective in promoting preferential displacement of oneprecursor flowable liquid by another, even on such very low surfaceenergy surfaces as the fluorinated surfaces of e.g. fluorosiliconerelease liners. As is known by the skilled artisan, fluorinated surfacessuch as e.g. fluorosilicones are very low in surface energy (i.e., theymay exhibit surface energies that may be in the teens, or even in singledigits, in dynes/cm). Such surfaces are thus expected to be difficult towet, particularly by liquids that have comparatively high surfaceenergies (e.g., liquids comprising high-surface-energy-imparting polargroups).

As documented in the Working Examples herein, commonplace organicpolymeric adhesives may be coated out of very non-polar coatingsolutions (e.g., out of toluene and the like). In contrast,silicone-based adhesives, particularly those comprising polar moieties(e.g., urea linkages, polyoxamide linkages, and so on), are often coatedout of coating solutions that are considerably more polar (e.g., amixture of isopropyl alcohol and toluene for exemplary silicone-polyureamaterials, and a mixture of isopropyl alcohol, ethyl acetate, andtoluene for exemplary silicone-polyoxamide materials). It would thus beexpected that relatively non-polar coating solutions (e.g., comprisingtoluene as the only solvent) would be more able to wet such a low energysurface as a fluorosilicone surface of a release liner, in comparison tocoating solutions comprising appreciable amounts of e.g. isopropylalcohol and/or ethyl acetate. However, as documented in the WorkingExamples herein, the inventors have been able to obtain enrichment ofsilicone-based adhesive stripes 20, relative to organic polymericadhesive stripes 40, on the surface of an adhesive layer 5 that is incontact with the fluorosilicone surface of a release liner. Thisindicates that the coating solutions of these silicone adhesives may beable to preferentially displace the coating solutions of the organicpolymeric adhesives on the surface of the fluorosilicone release liner,even though the coating solutions of the silicone-based adhesives shouldhave a higher surface energy than those of the organic polymericadhesives. Based on these factors, the herein-described surfaceenrichment would be unexpected to the skilled artisan.

It should be noted that it is possible that at least some of any suchdisplacement of the organic polymeric adhesive coating solution by thesilicone-based adhesive coating solution might occur in the later stagesof the process, e.g. after significant portions of the solvent(s) havebeen removed from the respective coating solutions. As such, it might beconjectured that a lower surface energy of a silicone-based adhesiveitself (in comparison to that of the organic polymeric adhesive) mightplay a role. However (possibly due to an effect in which the presence incertain silicone adhesives of high-surface-energy imparting polarmoities such as urea or oxamide linkages, etc., may somewhat offset thelow surface energy of e.g. polysiloxane portions of the siliconeadhesives), the surface energies of exemplary silicone-based adhesivescomprising such polar moities have not been found to be significantlylower than the surface energy of exemplary organic polymeric adhesives.Specifically, surface energies in the range of 34 dyne/cm have beenfound for exemplary silicone-based adhesives, versus in the range of 39dyne/cm for exemplary organic polymeric adhesives (both of which are farabove the surface energy of typical fluorosilicone surfaces).

Thus, the surface-enrichment that is described herein and that isdocumented in numerous Working Examples, remains a surprising resultthat would not be expected based on the properties of the variousadhesives themselves and/or their precursor coating solutions, or on theproperties of fluorinated release liners. Nor would it be expected basedon the known behavior of e.g. die-coating operations as customarilyperformed by those of skill in the art.

Once the coating/solidification is process is complete (that is, whenstripes of adhesive 20 and 40 are in their final form so as tocollectively comprise adhesive layer 5 upon major surface 11 ofsubstrate 10), substrate 10 bearing adhesive layer 5 thereupon can bee.g. wound and stored as a continuous roll until ready for furtherprocessing. In some embodiments, substrate 10 may comprise a releasecoating, e.g. a fluorosilicone release coating, on surface 12 to ensurethat the roll can be unwound as desired. Or, substrate 10 bearingadhesive layer 5 thereupon can be further processed without being rolledup and/or stored, as desired. In some embodiments adhesive layer 5 canbe adhesively bonded (e.g., laminated) to a tape backing e.g. to form apressure-sensitive adhesive tape. In some embodiments such an adhesivetape can be a single-faced (sided) tape. In other embodiments, a secondadhesive layer (and a second release liner, if desired) can be laminatedto the opposite side of the tape backing to form a double-faced adhesivetape. If desired, such a tape backing can be highly extensible so thatthe formed tape (whether single or double faced) can serve as astretch-releasable adhesive tape.

LIST OF EXEMPLARY EMBODIMENTS Embodiment 1

A method of making an article, the method comprising: simultaneouslyexpelling a first precursor liquid of a first pressure-sensitiveadhesive through a first set of multiple, laterally-spaced-apartopenings in a coating die and simultaneously expelling a secondprecursor coating liquid of a second pressure-sensitive adhesive througha second set of multiple, laterally-spaced-apart openings in the samecoating die, wherein the openings of the first set and the openings ofthe second set are arranged in a generally alternating pattern with eachother so that generally-alternating streams of the first and secondprecursor liquids are expelled therefrom and are deposited onto asurface of a substrate that is continuously moving past the coating die;allowing, for at least selected laterally-adjacent streams of the firstand second precursor liquids, a lateral edge of the deposited firstprecursor liquid to laterally displace a lateral edge of the depositedsecond precursor liquid at the surface of the substrate, and,solidifying the first precursor liquid into the first pressure-sensitiveadhesive and solidifying the second precursor liquid into the secondpressure-sensitive adhesive, thereby forming generally alternatingstripes of the first and second pressure-sensitive adhesives on thesubstrate, wherein at least for selected stripes, the lateral displacingof a lateral edge of the second precursor liquid by a lateral edge ofthe first precursor liquid at the surface of the substrate causes alateral edge portion of the first pressure-sensitive adhesive stripe toinwardly underlie, and to be in contact with, a lateral edge portion ofa laterally-adjacent second pressure-sensitive adhesive stripe, andcauses a substrate-side lateral width of the first pressure-sensitiveadhesive stripe to be greater than an opposite-side lateral width of thefirst pressure-sensitive adhesive stripe by a factor of at least about1.2.

Embodiment 2

The method of embodiment 1 wherein the first and second precursorliquids are first and second coating solutions.

Embodiment 3

The method of embodiment 2 wherein the first and second coatingsolutions comprise first and second pressure-sensitive adhesivecompositions each dissolved in a solution comprising one or more organicsolvents.

Embodiment 4

The method of any of embodiments 1-3, wherein after the selected streamsof the first precursor liquid and the second precursor liquid aredeposited on the surface of the substrate and before the precursorliquids are solidified, the deposited first precursor liquid comprises athickness that is at least about 1.4 times the thickness of thedeposited second precursor liquid.

Embodiment 5

The method of embodiment 4 wherein the deposited first and secondprecursor liquids, prior to being solidified, are passed through athickness-control gap that defines a distance between athickness-control member and the surface of the substrate, whichthickness-control gap is shorter in height than a thickness of thedeposited first precursor liquid.

Embodiment 6

The method of any of embodiments 1-5, wherein the substrate is a releaseliner.

Embodiment 7

The method of any of embodiments 1-6, wherein the firstpressure-sensitive adhesive is a silicone-based pressure-sensitiveadhesive and wherein the second pressure-sensitive adhesive is anorganic polymeric pressure-sensitive adhesive.

Embodiment 8

The method of embodiment 7, wherein the organic polymericpressure-sensitive adhesive comprises an organic elastomer selected fromthe group consisting of styrenic block copolymer elastomers, naturalrubber elastomers, (meth)acrylate elastomers, and mixtures and blendsthereof.

Embodiment 9

The method of any of embodiments 1-8 wherein at least selected streamsof the first precursor liquid are laterally flanked by first and secondstreams of the second precursor liquid, and wherein first and secondlateral edges of the first precursor liquid are caused to laterallydisplace lateral edges of the first and second streams of the secondprecursor liquid at the surface of the substrate.

Embodiment 10

The method of any of embodiments 1-9 wherein the solidifying of thefirst and second precursor liquids comprises the evaporation of solventfrom both liquids.

Embodiment 11

The method of any of embodiments 1-10 wherein the solidifying of thefirst and second precursor liquids comprises the reaction of functionalgroups in at least one of the first and second precursor liquids.

Embodiment 12

The method of any of embodiments 1-11, further comprising the step ofcontacting major surfaces of the generally alternating stripes of thefirst and second pressure-sensitive adhesives, which major surfaces faceoppositely from the substrate, to a highly extensible tape backing andbonding the stripes of the first and second pressure-sensitive adhesiveto the highly extensible tape backing to form a stretch-releasable tapearticle.

Embodiment 13

An article comprising: a substrate comprising a first major surface; aprimary adhesive layer disposed on the first major surface of thesubstrate, wherein the primary adhesive layer comprises a plurality ofstripes of a first pressure-sensitive adhesive and of a secondpressure-sensitive adhesive, arranged in a generally alternating patternacross a lateral extent of the substrate; wherein for at least forselected stripes of the first pressure-sensitive adhesive, a lateraledge portion of the first pressure-sensitive adhesive stripe inwardlyunderlies, and is in contact with, a lateral edge portion of a secondpressure-sensitive adhesive stripe that is laterally adjacent to thefirst pressure-sensitive adhesive stripe, and, a substrate-side lateralwidth of the first pressure-sensitive adhesive stripe is greater than anopposite-side lateral width of the first pressure-sensitive adhesivestripe by a factor of at least about 1.2.

Embodiment 14

The article of embodiment 13, wherein the first pressure-sensitiveadhesive stripe comprises a laterally-central portion with a secondmajor surface that faces generally opposite the first major surface ofthe first pressure-sensitive adhesive stripe, which second major surfaceof the laterally-central portion of the first pressure-sensitiveadhesive stripe is not in contact with or covered by the secondpressure-sensitive adhesive stripe.

Embodiment 15

The article of embodiment 14 wherein at least a part of the lateral edgeportion of the first pressure-sensitive adhesive stripe comprises athickness that is less than about 20% of an average thickness of thelaterally-central portion of the first pressure-sensitive adhesivestripe.

Embodiment 16

The article of any of embodiments 14-15 wherein the lateral edge portionof the first pressure-sensitive adhesive stripe comprises an averagelateral width that is at least 20% of an average lateral width of thelaterally-central portion of the first pressure-sensitive adhesivestrip.

Embodiment 17

The article of any of embodiments 13-16, wherein the firstpressure-sensitive adhesive provides a substrate-side area fraction onthe substrate-facing surface of the primary adhesive layer and providesan opposite-side area fraction on the side of the primary adhesive layerthat is opposite the substrate, and wherein the primary adhesive layerexhibits a first pressure-sensitive adhesive surface-enrichment factorthat is the ratio of the substrate-side area fraction of the firstpressure-sensitive adhesive to the opposite-side area fraction of thefirst pressure-sensitive adhesive, and wherein the firstpressure-sensitive adhesive surface-enrichment ratio is at least about1.2.

Embodiment 18

The article of embodiment 17, wherein the first pressure-sensitiveadhesive surface-enrichment ratio is at least about 1.6.

Embodiment 19

The article of any of embodiments 13-18, wherein the firstpressure-sensitive adhesive provides a volume fraction of the primaryadhesive layer that is from about 30% to about 90%.

Embodiment 20

The article of any of embodiments 13-19, wherein the firstpressure-sensitive adhesive provides a volume fraction of the primaryadhesive layer that is from about 40% to about 80%.

Embodiment 21

The article of any of embodiments 13-20, wherein the firstpressure-sensitive adhesive provides an overall area fraction, on a sideof the primary adhesive layer that is opposite the substrate, of fromgreater than about 20%, to about 70%.

Embodiment 22

The article of any of embodiments 13-21, wherein the firstpressure-sensitive adhesive provides an overall area fraction, on a sideof the primary adhesive layer that is opposite the first substrate, offrom greater than about 30%, to about 60%.

Embodiment 23

The article of any of embodiments 13-22, made by the method of any ofembodiments 1-12.

Examples

Test Procedures

Test procedures used in the Examples include the following.

Measurement of Stripe Parameters

To perform thickness measurements of stripes, samples were cut with asharp razorblade at random locations and thicknesses determinedoptically via an Olympus Optical Microscope. All measurements wererecorded in mils (thousandths of an inch).

Stripe width and stripe pitch (center-to-center distance betweenadjacent stripes or sub-stripes) were measured using an Olympus OpticalMicroscope. At least three measurements were taken at random locationson the sample and averaged. Even in the presence of substrate-sidesurface-enrichment, it was usually possible to obtain the substrate-sideand opposite-side widths of the first and second stripes by opticalinspection. That is, with backlit samples, areas in which the lateralportions of two adhesive stripes of adhesive overlapped (i.e., areaw_(le) as shown in FIG. 1) typically exhibited at least a slight opacityor whitening (thought to be caused by slight interfacial effects betweenthe two adhesives) in comparison to the relatively transparent stripesof each adhesive. So, for any given stripe of e.g. first adhesive 20,optical inspection could usually provide the substrate-side width of thestripe (corresponding to the herein-mentioned W_(lc) plus two timesw_(le)) and also the opposite-side width of the stripe. As mentioned,the opposite-side width of a stripe was usually measured by opticalinspection of that surface of the stripe; that is, it usuallycorresponded to W_(lc) as shown in FIG. 1. The exception was cases inwhich slight surface-enrichment was present at the opposite side of thestripe (as illustrated in the exemplary embodiment of FIG. 3). In suchcases, the minimum width of the stripe (as denoted by the double-headedarrow in FIG. 3) was used as the opposite-side width W_(lc). Suchminimum widths could be obtained by e.g. cutting cross-sectional samplesin similar manner as described above for obtaining stripe thicknesses.

Area Fractions and Volume Fractions

The various area fractions described herein could be straightforwardlycalculated from the average widths of the stripes. Volume fractionscould also be calculated from the average widths of the stripes, byfurther taking into account the thicknesses of the adhesive stripes. Thevolume fractions herein are nominal numbers obtained from measurementsof the opposite-side widths and area fractions of the respectivestripes, with a +5% correction factor applied thereto based on the knownsurface enrichment at the substrate side. These volume fractions aremarked accordingly in the Tables.

Elevated Humidity/Static Shear Test Method

Elevated Humidity/Static Shear Test Method tests were performed ingenerally similar manner to those outlined in U.S. patent applicationSer. No. 61/838,504, Entitled “Article Comprising Pressure-SensitiveAdhesive Stripes”, filed evendate herewith.

Materials

Substrate (Release Liner) and Tape Backing

Fluorosilicone release liner of the general type designated as SYL-OFFQ2-7785, and multilayer composite foam laminate backing (thicknessapproximately 36 mils), were obtained, of the types described in theExamples section of U.S. Pat. No. 8,344,037 (Sherman).

Organic Polymeric Pressure-Sensitive Adhesive Coating Solution

An organic polymeric pressure-sensitive adhesive composition comprisingstyrene-butadiene-styrene block copolymer elastomers was preparedgenerally according to composition D of U.S. Pat. No. 6,231,962 (Bries).The solution as prepared comprised this adhesive composition atapproximately 43 wt. % (total) solids in toluene, and was diluted withtoluene to approximately 35% solids to form a coating solution. Thecoating solution exhibited a viscosity (Brookfield LVT, #3 spindle, 6rpm, for this and all other viscosities listed here) in the range ofapproximately 1500 cP. This adhesive was designated as PSA-O-1. Allstripes of organic polymeric adhesive in the following Working Examplesused this adhesive.

Silicone-Based Pressure-Sensitive Adhesive Coating Solution—SPU

A pressure-sensitive adhesive composition was prepared that comprised asilicone-polyurea (SPU) elastomer in combination with a functional MQresin. The composition was prepared generally according to Example 27 ofU.S. Pat. No. 6,569,521 (Sheridan), with the difference that the ratioof components was altered to achieve a pressure-sensitive adhesivecomposition with MW PDMS diamine/moles Dytek A polyamine/% by weight MQresin of 33000/0.5/50 (that is, with the silicone-polyurea elastomer andthe MQ resin being at an approximately 50/50 weight ratio). The coatingsolution comprised this adhesive composition at approximately 30 wt. %total solids in a 70/30 (wt. %) blend of toluene/isopropanol. Thecoating solution exhibited a viscosity of approximately 8700 cP. Thisadhesive was designated as PSA-S-1.

Silicone-Based Pressure-Sensitive Adhesive Precursor CoatingSolution—SPOx

A pressure-sensitive adhesive composition was obtained that comprised asilicone-polyoxamide (SPOx) elastomer in combination with a functionalMQ resin. The silicone-polyoxamide elastomer was believed to be similarin structure and properties to the elastomer described as “PSA 2” in theWorking Examples of U.S. Patent Application Publication No. 2009/0229732(Determan). The functional MQ resin was procured from GE under the tradedesignation SR-545 (as was the MQ resin used in PSA-S-1). Thesilicone-polyoxamide elastomer and the MQ resin were at a 50/50 weightratio. The coating solution comprised this adhesive composition atapproximately 35 wt. % total solids in a 60/20/20 (wt. %) blend of ethylacetate/isopropanol/toluene. The coating solution exhibited a viscosityof approximately 7600 cP. This adhesive was designated as PSA-S-2. Thestripes of silicone-based adhesives in Tables 1 and 2 used thissilicone-based adhesive.

Coating Process

Representative Coating Process

The coating solutions were wet coated on the SYL-OFF Q2-7785 releaseliner in stripes using a dual layer slot die. The two layers of the slotdie were fed from separate manifolds (one to feed a first coatingsolution, the other to feed a second coating solution, with separateshims being provided for each manifold/slot layer). Each shim comprisedopenings of desired width and spacing to expel coating solutiontherethrough so as to form stripes of that coating solution of thedesired width and pitch. The two shims were registered in relation toeach other so as to deposit stripes in a generally alternating patternas desired. In typical experiments, the total width of the coating areawas approximately 2 inches.

Representative experiments were conducted with a first coating solutioncomprising PSA-O-1 (organic polymeric adhesive) and with a secondcoating solution comprising PSA-S-1 (silicone-based adhesive). The twocoating solutions were fed to their respective slot layers at a feedrate of approximately 22 cc/min (in a few cases, the flowrate of thePSA-S-1 coating solution was kept at 22 cc/min and the flowrate of thePSA-O-1 coating solution was increased to 44 cc/min). Coatingexperiments were done at various line speeds, including 10, 20, 30, 40and 50 feet per minute. After coating, the stripe-coated release linerwas passed through a 3-zone forced air oven with zones operatingrespectively at approximately 57° C., 74° C. and 85° C. zonetemperatures to yield a dry coating of the pressure-sensitive adhesive.After drying, the release liner, bearing the dried adhesive layer on thefluorosilicone release surface thereof, was rolled up and stored atambient conditions until used.

Variations

Numerous variations of the above Representative Coating Process weredone, including experiments with PSA-S-2 as the second coating solution.The method in which the coating solutions were delivered were alsovaried; e.g., apparatus was used in which flow passages were integratedas part of the die itself (in generally similar manner to thearrangements described previously herein), and in which the number anddesign of die shims were varied. It is believed that these variations inthe particular manner in which the coating solutions were passed throughthe interior of the die did not significantly affect the behavior of thecoating solutions once the solutions were coated on the release liner.That is, they did not appear to significantly affect theherein-described preferential displacement of one coating solution byanother.

Converting

A release liner bearing a primary adhesive layer thereon was typicallystored in roll form until used. Then, the liner was unrolled (to exposethe surface of the primary adhesive opposite the release liner) and theexposed surface of the primary adhesive layer was laminated to a foambacking. The layers were arranged so that the long axes of the adhesivestripes were oriented perpendicularly to the long axis of the foambacking unless otherwise noted. A secondary adhesive layer (bearing asecondary release liner) was then laminated to the opposite side of thefoam backing. Often the secondary adhesive layer was a continuouscoating of the organic polymeric adhesive of Comparative Example PSA-O-1(described below).

The thus-formed double-faced adhesive article could then be stored untilused.

EXAMPLES Single-Adhesive Comparative Examples

Comparative Example PSA-O-1 comprised a continuous coating of PSA-O-1(organic polymeric adhesive). To do this, the coating solution wasexpelled from the die-slot openings in discrete streams, but theflowrate of coating solution was such, and the release liner passed bythe die in such manner, that the deposited stripes laterally merged witheach other to form a continuous coated layer. Comparative ExamplePSA-O-1, when formed into a stretch-releasable tape and tested in theElevated Humidity/Static Shear Test Method, exhibited a test result(time to failure) of approximately 2500 minutes.

Comparative Example PSA-S-2 comprised a continuous coating of PSA-S-2(silicone-based adhesive in which the silicone elastomer was a siliconepolyoxamide), coated in generally similar manner as Comparative ExamplePSA-O-1. Comparative Example PSA-S-2, when formed into astretch-releasable tape and tested in the Elevated Humidity/Static ShearTest Method, exhibited a test result (time to failure) of >30000minutes. Although not included herein as a specific Comparative Example,it is noted that continuous coatings of PSA-S-1 (silicone-based adhesivein which the silicone elastomer was a silicone polyurea) had similarlybeen found to meet the >30000 minute threshold in such testing.

Stripe-Coated Working Examples

In order to save space in the Tables, it is stipulated that all WorkingExamples in the following Tables exhibited a result of >30000 minuteswhen formed into a stretch-releasable tape and tested in an ElevatedHumidity/Static Shear Test, excepting single-adhesive ComparativeExamples C1 and C2 as discussed above. Also, in all of the followingExamples the silicone-based adhesive was PSA-S-2 (in which the siliconeelastomer was a silicone polyoxamide). To save space in the followingTables, the following abbreviations are used in the Tables:

Key Abbrevi- ation Units Parameter T-S Mils Thickness of silicone-basedadhesive stripes T-O Mils Thickness of organic polymeric adhesivestripes P Mm Pitch, in mm W-S (LS) Mils Width of silicone-based adhesivestripes (liner side) W-S (OS) Mils Width of silicone-based adhesivestripes (opposite side) W-O (LS) Mils Width of organic polymericadhesive stripes (liner side) W-O (OS) Mils Width of organic polymericadhesive stripes (opp. side) AF-S (LS) % Area fraction, siliconeadhesive (liner side) AF-S (OS) % Area fraction, silicone adhesive(opposite side) VF-S % Volume fraction, silicone adhesive (for selectedexamples)

The width (W) and thickness (T) of the various stripes were measuredoptically as described previously. The pitch (P, reported in mm) wasindicative of the overall (average) center-to-center distance betweenadjacent stripes (and sub-stripes, if present). The stripe pitch wastypically fairly uniform with the center-to-center distance between anytwo specific stripes closely approximating the overall average pitch.For clarity of presentation, in Tables 1 and 2 the widths of the variousstripes in the silicone surface-enriched samples are omitted. Areafractions were calculated from the measured stripe widths as describedabove.

Table 1 shows parameters for stripes with surface-enrichment of thefirst, silicone-based adhesive being observed at the surface of theadhesive layer that was in contact with the release liner (i.e., stripesof the general arrangement of FIG. 1). These samples were all of the20/40/20/40 generally alternating pattern. In Table 1, the opposite-sideand liner-side area fractions are only listed for the first,silicone-based adhesive. The balance of the opposite-side and liner-sidearea fractions were occupied by the second, organic polymeric adhesive.Estimated volume fractions of the first, silicone-based adhesive arelisted for selected samples.

TABLE 1 No. AF-S (OS) AF-S (LS) T-S T-O P VF-S 1-1 33 69 2.5 1.8 1.3 ~421-2 46 89 1.6 1.4 1.3 1-3 52 77 1.1 2.2 2.1 1-4 55 90 2.4 1.7 1.3 1-5 5696 2.3 2.0 1.3 ~61

In these data, comparison of the liner-side surface area fraction ofsilicone adhesive (AF-S (LS)) to the opposite-side fraction of siliconeadhesive (AF-S(OS)) reveals the surface-enrichment of the liner-sidesurface of the adhesive layer that can be attained. For example, WorkingExample 1-1 had an opposite-side area fraction of silicone adhesive ofapproximately 33%, and yet the surface of the adhesive layer against therelease liner was found to exhibit a silicone adhesive area fraction ofapproximately 69%, illustrating the ability of the silicone-basedadhesive to preferentially displace the organic polymeric adhesive, atthe surface of the adhesive layer that was in contact with the releaseliner.

To further illustrate the surface-enrichment phenomenon at the substratesurface, Table 1A presents the actual optically observed widths of thesilicone-based adhesive stripes at the release liner surface (W-S(LS))versus the optically observed widths of these stripes at the oppositesurface (W-S(OS)). The widths for the organic polymeric adhesive stripesare also listed in Table 1A. (The surface area fractions ofsilicone-based adhesive listed in Table 1 were calculated from the widthdata of Table 1A.) With respect to the aforementioned W_(lc) and w_(le)parameters, it will be appreciated that the W-S(OS) parametercorresponds to W_(lc) and that the W-S(LS) parameter corresponds toW_(lc)+w_(le)+

TABLE 1A No. W-S (LS) W-S (OS) W-O (LS) W-O (OS) 1-1 73.9 35.0 32.7 71.51-2 90.0 46.6 10.6 54.1 1-3 133.2 89.5 40.6 84.3 1-4 94.5 57.3 10.6 47.81-5 101 58.5 4.1 46.5

Table 2 shows parameters for stripes in which completesurface-enrichment of the first, silicone-based adhesive was observed atthe surface of the adhesive layer that was in contact with the releaseliner (i.e., stripes of the general arrangement of FIG. 2). In Table 2,the opposite-side and liner-side area fractions are only listed for thefirst, silicone-based adhesive. For these samples, the balance of theopposite-side and liner-side area fractions were occupied by the second,organic polymeric adhesive.

TABLE 2 No. AF-S (OS) AF-S (LS) T-S T-O P VF-S 2-1 48 100 2.1 2.0 1.32-2 51 100 3.1 2.3 1.3 2-3 53 100 1.7 1.5 1.6 2-4 57 100 2.4 1.7 2.5 ~692-5 58 100 2.6 1.9 1.5 2-6 61 100 3.0 1.3 2.1 ~82

In these data, comparison of the liner-side surface area fraction ofsilicone adhesive (AF-S (LS)) to the opposite-side fraction of siliconeadhesive (AF-S(OS)) reveals the high degree of surface enrichment of theliner-side surface that can be achieved if desired. For example, WorkingExample 2-1 had an opposite-side area fraction of silicone ofapproximately 48%, and yet the surface of the adhesive layer against therelease liner was found to exhibit a silicone adhesive area fraction ofapproximately 100%, indicating that the silicone adhesive had completelypreferentially displaced the organic polymeric adhesive at the surfaceof the adhesive layer that was in contact with the release liner. It wassometimes found that some enrichment of the first (silicone-based)adhesive also occurred on the surface of the adhesive layer opposite therelease liner (that is, the surface that was exposed to air afterdeposition of the coating solution on the release liner). Such samplesoften exhibited an appearance generally similar to that shown in FIG. 3.Typically, the extent of the surface-enrichment on this surface was notas great as that on the release liner surface.

The foregoing Examples have been provided for clarity of understandingonly. No unnecessary limitations are to be understood therefrom. Thetests and test results described in the Examples are intended solely tobe illustrative, rather than predictive, and variations in the testingprocedure can be expected to yield different results. All quantitativevalues in the Examples are understood to be approximate in view of thecommonly known tolerances involved in the procedures used.

It will be apparent to those skilled in the art that the specificexemplary structures, features, details, configurations, etc., that aredisclosed herein can be modified and/or combined in numerousembodiments. (In particular, all elements that are positively recited inthis specification as alternatives, may be explicitly included in theclaims or excluded from the claims, in any combination as desired.) Allsuch variations and combinations are contemplated by the inventor asbeing within the bounds of the conceived invention not merely thoserepresentative designs that were chosen to serve as exemplaryillustrations. Thus, the scope of the present invention should not belimited to the specific illustrative structures described herein, butrather extends at least to the structures described by the language ofthe claims, and the equivalents of those structures. To the extent thatthere is a conflict or discrepancy between this specification as writtenand the disclosure in any document incorporated by reference herein,this specification as written will control.

What is claimed is:
 1. A method of making an article, the methodcomprising: simultaneously expelling a first precursor liquid of a firstpressure-sensitive adhesive through a first set of multiple,laterally-spaced-apart openings in a coating die and simultaneouslyexpelling a second precursor coating liquid of a secondpressure-sensitive adhesive through a second set of multiple,laterally-spaced-apart openings in the same coating die, wherein theopenings of the first set and the openings of the second set arearranged in a generally alternating pattern with each other so thatgenerally-alternating streams of the first and second precursor liquidsare expelled therefrom and are deposited onto a surface of a substratethat is continuously moving past the coating die; allowing, for at leastselected laterally-adjacent streams of the first and second precursorliquids, a lateral edge of the deposited first precursor liquid tolaterally displace a lateral edge of the deposited second precursorliquid at the surface of the substrate, and, solidifying the firstprecursor liquid into the first pressure-sensitive adhesive andsolidifying the second precursor liquid into the secondpressure-sensitive adhesive, thereby forming generally alternatingstripes of the first and second pressure-sensitive adhesives on thesubstrate, wherein at least for selected stripes, the lateral displacingof a lateral edge of the second precursor liquid by a lateral edge ofthe first precursor liquid at the surface of the substrate causes alateral edge portion of the first pressure-sensitive adhesive stripe toinwardly underlie, and to be in contact with, a lateral edge portion ofa laterally-adjacent second pressure-sensitive adhesive stripe, andcauses a substrate-side lateral width of the first pressure-sensitiveadhesive stripe to be greater than an opposite-side lateral width of thefirst pressure-sensitive adhesive stripe by a factor of at least about1.2, and wherein the first pressure-sensitive adhesive occupies anoverall area fraction, on a side of the first and secondpressure-sensitive adhesive stripes that faces the surface of thesubstrate, of less than 100%.
 2. The method of claim 1 wherein the firstand second precursor liquids are first and second coating solutions. 3.The method of claim 2 wherein the first and second coating solutionscomprise first and second pressure-sensitive adhesive compositions eachdissolved in a solution comprising one or more organic solvents.
 4. Themethod of claim 1, wherein after the selected streams of the firstprecursor liquid and the second precursor liquid are deposited on thesurface of the substrate and before the precursor liquids aresolidified, the deposited first precursor liquid comprises a thicknessthat is at least about 1.4 times the thickness of the deposited secondprecursor liquid.
 5. The method of claim 4 wherein the deposited firstand second precursor liquids, prior to being solidified, are passedthrough a thickness-control gap that defines a distance between athickness-control member and the surface of the substrate, whichthickness-control gap is shorter in height than a thickness of thedeposited first precursor liquid.
 6. The method of claim 1, wherein thesubstrate is a release liner.
 7. The method of claim 1, wherein thefirst pressure-sensitive adhesive is a silicone-based pressure-sensitiveadhesive and wherein the second pressure-sensitive adhesive is anorganic polymeric pressure-sensitive adhesive.
 8. The method of claim 7,wherein the organic polymeric pressure-sensitive adhesive comprises anorganic elastomer selected from the group consisting of styrenic blockcopolymer elastomers, natural rubber elastomers, (meth)acrylateelastomers, and mixtures and blends thereof.
 9. The method of claim 1wherein at least selected streams of the first precursor liquid arelaterally flanked by first and second streams of the second precursorliquid, and wherein first and second lateral edges of the firstprecursor liquid are caused to laterally displace lateral edges of thefirst and second streams of the second precursor liquid at the surfaceof the substrate.
 10. The method of claim 1 wherein the solidifying ofthe first and second precursor liquids comprises the evaporation ofsolvent from both liquids.
 11. The method of claim 1 wherein thesolidifying of the first and second precursor liquids comprises thereaction of functional groups in at least one of the first and secondprecursor liquids.
 12. The method of claim 1, further comprising thestep of contacting major surfaces of the generally alternating stripesof the first and second pressure-sensitive adhesives, which majorsurfaces face oppositely from the substrate, to a highly extensible tapebacking and bonding the stripes of the first and secondpressure-sensitive adhesive to the highly extensible tape backing toform a stretch-releasable tape article.